Captured fastener device

ABSTRACT

Provided is at least one finger that allows securing of various sizes of bolts, undersized or oversized. Flow channels in a compression limiter allow plastic to flow from an outer portion of the compression limiter to a center of the compression limiter to form the angled fingers. The angled fingers allow cheaper manufacture of the compression limiter. The length of the compression limiter may be manufactured using lower tolerances. Also, the inner diameter of the compression limiter does not need an angled step to or tight tolerances, which allows less costly manufacturing of the compression limiter.

RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No.62/048,077 filed Sep. 9, 2014, which is hereby incorporated herein byreference.

FIELD OF INVENTION

The present invention relates generally to assemblies, and moreparticularly to a captured fastener apparatus and a method of making thesame.

BACKGROUND

Articles having bolt-receiving openings have been used in assemblies forvarious purposes. Frequently the articles are fastened to other objectsor articles by using a nut and a bolt or other metal threaded fastener.Typically, bolts are pre-assembled into a bolt hole in the articles tofacilitate bolting the articles to the other objects or articles. Atubular thermoplastic retainer, such as an AXI-RAD®, is often installedon the bolts (or other threaded fastener) and inserted into acompression limiter (e.g., a metal compression limiter) of the articlesto secure the bolts to the articles and maintain alignment prior toassembly.

Typically, the compression limiter is pressed into a bore in thearticles and receives the tubular thermoplastic retainer and the bolt.The compression limiter strengthens the article (particularly whenformed from plastic) and resists the load that is applied thereto. Theintegrity of the article, therefore, is not compromised. Additionally,the compression limiter prevents/reduces material creep which can causereduction of the fastener tightening torque over time.

Traditional retention mechanisms, like the tubular thermoplasticretainer designs, require multiple assembly steps and tight tolerancesto match the size of a corresponding bolt (e.g., a diameter of theretention mechanism must be within ±0.005″ of a diameter of the bolt). Atypical tubular thermoplastic retainer design requires inserting thecompression limiter into the article, later inserting the bolt into atubular thermoplastic retainer, and later inserting the bolt and thetubular thermoplastic retainer into the compression limiter to securethe bolt to the article. Tolerances needed to be tight for the article,compression limiter, and tubular thermoplastic retainer. Otherwise, thefastener may be unsecured and/or misalignment may occur, which can leadto added costs due to manual labor required to align the bolt, wasteddefective materials, and/or delay.

SUMMARY OF INVENTION

The present disclosure provides a captured fastener apparatus thatincludes at least one finger for securing various sizes of fasteners,including undersized or oversized fasteners. In forming the at least onefinger, flow channels in a compression limiter allow a material, such asplastic, to flow from an outer portion of the compression limiter to acenter of the compression limiter to form one or more angled fingers.The one or more angled fingers enable the compression limiter to bemanufactured at a reduced cost and/or enable the compression limiter tobe manufactured using lower tolerances. Also, an inner diameter of thecompression limiter does not need an angled step or tight tolerances,which allows use of less costly manufacturing techniques for thecompression limiter.

According to one aspect of the invention, an assembly component includesa body having a through aperture defined by an interior surface of thebody for receiving the shank of a fastener, and at least one resilientfinger projecting radially and axially into the aperture for engaging ata free end of the at least one finger the shank of the fastener, andwherein the free end is radially inwardly spaced from the interiorsurface for defining therebetween a radial gap that allows the free endto flex toward the interior surface for gripping and retaining the shankof the fastener in the aperture.

The body may include a main body portion formed of plastic and acompression limiter fixed in the body and forming the interior surface,the compression limiter being formed of a material less compressiblethan main body portion in a region proximate to the compression limiter.

The main body portion may be over-molded onto the compression limiter.

The body may include radially inwardly extending anchor portionsconnected to a base portion of the body.

The free end may be opposite a proximal end connected to the baseportion of the body.

The compression limiter may have a channel in which a fixed portion ofeach radially inwardly extending anchor portion is accommodated.

Each finger may be unitary with the main body portion.

The base portion may be unitary with each finger.

Each finger may project radially and axially into the aperture in anunflexed state of the finger.

The at least one finger may be a plurality of fingers that arecircumferentially spaced about the aperture.

The thickness of each finger may be less than a length of each finger,respectively.

A circumferential length of each finger may be greater than thethickness of each finger.

The thickness of each finger may be 5%-25% the length of each finger,respectively.

The thickness of each finger may be 10%-15% the length of each finger,respectively.

The assembly component may further include a circumferential spacingbetween each finger.

The circumferential length of each finger may be equal to or greaterthan a circumferential length of each circumferential spacing.

A component assembly including the assembly component may furtherinclude the shank of the fastener held within the aperture.

A method of securing a fastener to a body of the assembly may includeinserting a fastener into the aperture, and the free end of each fingermay be resiliently flexed radially and axially to apply a gripping forceto the shank of the fastener.

The compression limiter may include at least one channel for connectingto each finger of the body.

The compression limiter may include a plurality of channels forconnecting to each finger of the body.

The at least one resilient finger may include a radially inwardextending portion.

The radially inward extending portion may circumferentially span thefree end of the finger.

The foregoing and other features of the invention are hereinafterdescribed in greater detail with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of an exemplary exploded componentassembly.

FIG. 2 is a perspective view of the assembly of FIG. 1, with part of thecomponent assembly cut-away to show orientation of components.

FIG. 3 is a perspective view similar to FIG. 2, but with an enlargedview of a single fastener and with part of the component assemblycut-away at a different angle than FIG. 2.

FIG. 4 is a perspective view similar to FIG. 2, but with an enlargedview and the fastener being shown transparent to show orientation ofcomponents.

FIG. 5 is a perspective view similar to FIG. 4, but with the fastenerbeing shown opaque.

FIG. 6 a is a cross-section of the component assembly of FIG. 1 in anunflexed state.

FIG. 6 b is a cross-section of the component assembly of FIG. 1 in aflexed state.

FIG. 7 is a perspective view of another exemplary component assemblywith a radially inward extending portion for greater retention of afastener, with part of the component assembly cut-away and the fastenerbeing shown transparent.

FIG. 8 is a perspective view similar to FIG. 7, but with an enlargedview.

DETAILED DESCRIPTION

The principles in accordance with the present disclosure have particularapplication to assembly components that use fasteners to fasten theassembly components to other portions of a larger assembly, such as aplastic component of a vehicle, and thus will be described below chieflyin this context. It will of course be appreciated, and also understood,that the principles in accordance with the present disclosure may beapplicable to other components where it is desirable to secure afastener to the component.

Referring now in detail to the drawings, and initially to FIGS. 1-5, acomponent assembly 10 is illustrated. The component assembly includes abody 12 at least partially forming a plurality of fastener mountingfeatures 14 and a fastener 16 for each fastener mounting feature 14. Thecomponent assembly 10 may be a sub-assembly of a larger assembly (notshown) that includes the component assembly 10. The component assembly10 is secured, such as bolted, to another component (not shown) of thelarger assembly.

The component assembly 10 can be manufactured inexpensively compared totraditional component assemblies by molding the body 12 and at leastpart of each fastener mounting feature 14. Once the body 12 is molded,each fastener mounting feature 14 may receive the fastener 16 withoutany further assembly processes. Thus, the component assembly 10 requiresfewer assembly steps than the prior art (e.g., neither slidablyinserting a compression limiter nor slidably inserting a tubularthermoplastic retainer is required). Also, the dimensions of eachfastener mounting feature 14 can be manufactured using loose tolerancescompared to traditional retention systems to allow further costreductions with cheaper manufacturing and less wasted time or materialsdue to an out of tolerance fastener mounting feature 14.

Each fastener mounting feature 14 includes a through aperture 20 definedby an interior surface 22 of the body 12 for receiving the shank of thefastener 16 along a longitudinal axis A, radially inwardly extendinganchor portions 24-27, a base portion 30 and at least one resilientfinger 32, 34 projecting radially and axially into the aperture 20. Theaperture 20 allows the fastener 16 to move therethrough for theresilient fingers 32, 34 to secure and align the fastener 16 forconnection with a separate component (not shown). The entire body 12 maybe formed of any suitable material, such as metal or plastic, and may beformed by an injection molding process.

The radially inwardly extending anchor portions 24-27 connect to thebase portion 30. The anchor portions 24-27 allow the base portion 30 tobe radially inwardly spaced from the rest of the body 12 (excluding thefingers 32, 34) to form a guide surface for the fastener 16 to reach thefingers 32, 34 and a support surface for each finger 32, 34. Theradially inward position of the base portion 30 allows the fingers 32,34 to begin radially inward of the interior surface 22. The anchorportions 24-27 may be circumferentially spaced from one another tospread forces between the anchor portions 24-27. For example, in oneembodiment the anchor portions 24-27 may be equi-circumferentiallyspaced. In another embodiment the anchor portions 24-27 may beasymmetrically circumferentially spaced. In yet another embodiment onlyone anchor portion may be present. In yet another embodiment the baseportion 30 is not radially inwardly offset by an anchor portion.

The base portion 30 includes a circumferential portion with an axiallyextending ledge that each finger 32, 34 extends from. The base portion30 may be unitary with each finger 32, 34, which allows the base portion30 and each finger 32, 34 to be molded at the same time.

Each resilient finger 32, 34 projects radially and axially into theaperture 20 in an unflexed state of the finger 32, 34. Projectingradially and axially allows each resilient finger 32, 34 to spreadradially outward due to forces caused by insertion of the fastener 16,which reduces the risk of breaking or plastically deforming a resilientfinger 32, 34.

In addition to the illustrated resilient fingers 32 and 34, hidden fromview in FIG. 1 are two additional fingers with similar shape andorientation. The additional fingers may be arranged opposite theresilient fingers 32 and 34 to form a generally conical boundary spacedabout the aperture 20. Such additional resilient fingers may formed inthe same manner and exhibit the same properties and dimensions asresilient fingers 32 and 34. In an embodiment, the fingers form athrough aperture with a diameter having a tolerance between ±0.005″ and0.025″. Preferably, the tolerance of the diameter is between ±0.010″ and0.025″.

Each resilient finger 32, 34 is able to flex and exert a gripping forcewhen flexed to allow the fastener 16 to be inserted and secured withinthe aperture 20. Securing the fastener 16 allows the fastener 16 toremain aligned relative to the body 12 for later assembly of the body 12with another component. Each finger 32, 34 includes a free end 40, 42opposite a proximal end 50, 52 that is connected to the base portion 30.Each free end 40, 42 engages the shank of the fastener 16 and is able toflex radially and axially to receive the shank and exert a grippingforce to secure the fastener 16. For example, the shank may or may notinclude threaded portions of the fastener 16 and each free end 40, 42may or may not engage the threaded portions of the shank. Alternatively,each free end 40, 42 may engage a smooth portion of the shank.

Each proximal end 50, 52 is connected to the base portion 30, preferablyradially outward of the shank of the fastener 16. Each proximal end 50,52 being radially outward of the shank allows the shank to easily passthrough the aperture 20 until a portion of the shank reaches each freeend 40, 42.

Each resilient finger 32, 34 may have a thickness less than a respectivelength and circumferential length, about the longitudinal axis A, ofeach resilient finger 32, 34. The thickness of each finger 32, 34 may bematerial dependent and nominal wall thickness dependent. In anembodiment, the ratio of thickness to length or circumferential lengthof each finger is 1:5. As used herein, the circumferential length ofeach finger 32, 34 is a length along arc C, illustrated in FIG. 4, aboutthe longitudinal axis A. Forming the finger to have a thickness lessthan the length allows each resilient finger 32, 34 to flex and providea gripping force to hold the shank of the fastener. In an embodiment,the thickness is between 5% and 25%, preferably between 10% and 15%, thelength of each respective resilient finger. The thickness being lessthan the circumferential length allows each resilient finger 32, 34 tobound a larger portion of the shank of the fastener 16 to maintainalignment and increase the gripping force applied to the shank uponinsertion into the aperture 20.

Each fastener mounting feature 14 may include a spacing 80-82 openingaxially between adjacent radially outward portions of each resilientfinger 32, 34. The spacings 80-82 allow the resilient fingers 32 and 34to move independent of one another. The spacings 80-82 also allowgreater flexibility for each resilient finger 32, 34. Preferably, thecircumferential length of each resilient finger 32, 34 is greater thanthe circumferential length of each spacing 80-82. The greatercircumferential length of each resilient finger 32, 34 enables greatergripping force to be applied to the fastener 16 and allows betteralignment of the fastener 16. In an embodiment, the circumferentiallength of at least one resilient finger is equal to or less than atleast one corresponding spacing. Each spacing 80-82 may extend axiallyalong substantially the entire length of each respective resilientfinger 32, 34. In an embodiment, at least one spacing extends less than90% of the length of at least one resilient finger. In anotherembodiment, at least one spacing extends less than 25% the length of atleast one resilient finger allowing a greater gripping force to beapplied to hold the shank of the fastener 16.

During use, the fastener 16 is inserted into the aperture 20 and eachfree end 40, 42 of each finger 32, 34 is resiliently flexed radially andaxially to apply a gripping force to the shank of the fastener 16. Thefree ends 40 and 42 may move in a pivoting motion about a respectiveportion of each finger 32, 34 axially closer to the base portion 30. Forexample each free end 40, 42 may flex in an arcuate path, as shown inFIGS. 6 a and 6 b.

As shown in FIGS. 6 a and 6 b, each finger 32 and 34 is angled from thebase portion 30 at approximately the same angle in an unflexed state,illustrated in FIG. 6 a as 110°. As the fastener 16 slides into positionbetween the fingers 32 and 34 in FIG. 6 b, the free ends 40 and 42 flexradially and axially outward generally along the provided curved arrows.The flexing decreases the angle, illustrated for simplicity as 105°,between the base portion 30 and each finger 32, 34. Depending on theunflexed shape and orientation of each finger 32, 34, as the one or morefingers 32, 34 flex they may bow or arc between the base portion 30 andeach free end 40, 42, thus acting as an unsupported end of a loadedcantilever.

Referring again to FIGS. 1-5, flexing the free ends 40 and 42 afterinsertion allows the fastener 16 to be secured and aligned withoutanother assembly step. The fastener 16 may later be assembled to securethe body 12 with another component after storage, shipping, or simplyrepositioning to align the body 12 with the other component.

Each free end 40, 42 is radially inwardly spaced from the interiorsurface 22 for defining therebetween a radial gap 60, 62 that allows thefree end 40, 42 to flex toward the interior surface 22 for gripping andretaining the shank of the fastener in the aperture 20. Each radial gap60, 62 provides a space for each free end 40, 42 to flex into as thefastener 16 is inserted through the base portion 30 into the aperture20. In an embodiment, at least one of the free ends is not provided arespective radial gap to prevent the at least one of the free ends fromflexing. In another embodiment, a radial gap provides enough space for afree end to flex radially outward of the base portion 30.

Each fastener mounting feature 14 may include at least part of a mainbody portion 70 and a compression limiter 72. The main body portion 70may be unitary with each finger 32, 34 such that each is made from thesame molding. Molding the main body portion 70 and each finger 32, 34together allows overmolding the compression limiter 72 to secure thecompression limiter 72 and form the fingers 32, 34 in one molding step.The main body portion 70 may be formed of plastic or another moldablematerial to overmold and bound the compression limiter 72, which may beformed from metal. Overmolding the compression limiter allows easymanufacturing and lowers assembly time and errors that may occur with aninserted compression limiter 72.

The compression limiter 72 is fixed in the main body portion 70 with aradially outward extending ledge 73. The compression limiter forms aninterior surface 74 that extends axially and circumferentially along theinterior surface 22 and includes radially extending channels 76-79. Eachfinger 32, 34 allows the interior surface 74 to be axially linearwithout an interior ledge for supporting a component, such as a tubularthermoplastic retainer.

The compression limiter 72 is formed of a material less compressiblethan the main body portion 70 in a region proximate to the compressionlimiter 72. Forming the compression limiter 72 of a less compressiblematerial, such as metal allows the compression limiter 72 to reinforcethe main body portion 70, thereby providing a more secure connectionbetween the fastener 16 and another assembly. Further, each finger 32,34 allows the compression limiter to be made using a loose toleranceprocess such as molding (instead of machine turning), which allows thecompression limiter 72 to be formed, for example, from powdered metal.

Each channel 76-79 is equi-circumferentially spaced to accommodate afixed portion of each anchor portion 24-27. Accommodating the anchorportions 24-27 in such manner allows the fastener 16 to exert a grippingforce axially against the compression 72 rather than a more compressibleportion of the main body portion 70. Each channel 76-79 is formed in anaxially facing end of the compression limiter 72, including an axiallyfacing end of the radially outward extending ledge 73. In an embodiment,at least one of the channels is formed away from the axially facing endof the compression limiter, such as in an axially intermediate portionof the compression limiter. Alternatively, at least one of the channelsmay be formed at an axially facing end of the compression limiteropposite the radially outward extending ledge. During manufacturing,each channel 76-79 allows moldable material to flow over the compressionlimiter 72 to form the base portion 30 and the fingers 32 and 34.

An advantage of the captured fastener device in accordance with thepresent disclosure is that assembly time and cost of the larger assemblyis reduced by using the component assembly 10, which allowsinexpensively and reliably securing each fastener 16. Each fastener 16may be secured with each fastener mounting feature 14 to properly aligneach fastener 16 with a corresponding fastener receiver (not shown),such as a bolt hole, of the larger assembly. Aligning each fastener 16allows the component assembly 10 to be easily installed withoutrequiring readjustment of one or more of the fasteners 16 to align witha respective fastener receiver.

Turning now to FIGS. 7-8, another exemplary embodiment of the componentassembly is shown at 110. The component assembly 110 is substantiallythe same as the above-referenced component assembly 10, and consequentlythe same reference numerals but indexed by 100 are used to denotestructures corresponding to similar structures in the component assembly110. In addition, the foregoing description of the component assembly 10is equally applicable to the component assembly 110 except as notedbelow. Moreover, it will be appreciated upon reading and understandingthe specification that aspects of the component assemblies may besubstituted for one another or used in conjunction with one anotherwhere applicable.

The component assembly 110 includes a body 112 at least partiallyforming a plurality of fastener mounting features 114 and a fastener 116for each fastener mounting feature 114. In an embodiment, only onefastener mounting feature is formed.

Each fastener mounting feature 114 includes a through aperture 120defined by an interior surface 122 of the body 112 for receiving theshank of the fastener 116 along a longitudinal axis A, radially inwardlyextending anchor portions 124-127, a base portion 130 and at least oneresilient finger 132, 134 projecting radially and axially into theaperture 120.

A feature of the embodiment shown in FIGS. 7-8 is a radially inwardextending portion 190, 192 included with each resilient finger 132, 134.The radially inward extending portions 190 and 192 allow greatergripping force to be applied to the shank of the fastener by increasingflexing of each respective resilient finger 132, 134 when the fastener116 is inserted into the aperture 120. The thickness of the radiallyinward extending portions 190 and 192 may be about 75% the thickness ofeach respective resilient finger 132, 134. In an embodiment, thethickness of at least one of the radially inward extending portions isgreater than 75% the thickness of the respective resilient finger. Inanother embodiment, the thickness of at least one of the radially inwardextending portions is less than 75% the thickness of the respectiveresilient finger. The length of the radially inward extending portions190 and 192 is preferably 5%-25%, more preferably 10%-15%, the length ofeach respective resilient finger 132, 134. Each radially inwardextending portion 190, 192 allows a gripping force to be concentrated ona particular area of the shank, such as a threaded portion for enhancingretention of the fastener 116. In an embodiment, at least one of theradially inward extending portions 190, 192 deforms to engage threads onthe shank.

Each radially inward extending portion 190, 192 circumferentially spansa respective free end 140, 142 of each respective resilient finger 132,134. Circumferentially spanning each free end 140, 142 allows equalizingthe gripping force applied to the fastener 116 to better secure andalign the fastener 116. In an embodiment, at least one of the free endsdoes not include a radially inward extending portion. In anotherembodiment, at least one of the free ends includes more than oneradially inward extending portions.

Although the invention has been shown and described with respect to acertain embodiment or embodiments, it is obvious that equivalentalterations and modifications will occur to others skilled in the artupon the reading and understanding of this specification and the annexeddrawings. In particular regard to the various functions performed by theabove described elements (components, assemblies, devices, compositions,etc.), the terms (including a reference to a “means”) used to describesuch elements are intended to correspond, unless otherwise indicated, toany element which performs the specified function of the describedelement (i.e., that is functionally equivalent), even though notstructurally equivalent to the disclosed structure which performs thefunction in the herein illustrated exemplary embodiment or embodimentsof the invention. In addition, while a particular feature of theinvention may have been described above with respect to only one or moreof several illustrated embodiments, such feature may be combined withone or more other features of the other embodiments, as may be desiredand advantageous for any given or particular application.

1. An assembly component including: a body having a through aperturedefined by an interior surface of the body for receiving the shank of afastener; and at least one resilient finger projecting radially andaxially into the aperture for engaging at a free end of the at least onefinger the shank of the fastener, and wherein the free end is radiallyinwardly spaced from the interior surface for defining therebetween aradial gap that allows the free end to flex toward the interior surfacefor gripping and retaining the shank of the fastener in the aperture. 2.The assembly component of claim 1, wherein the body includes a main bodyportion formed of plastic and a compression limiter fixed in the bodyand forming the interior surface, the compression limiter being formedof a material less compressible than main body portion in a regionproximate to the compression limiter.
 3. The assembly component of claim2, where the main body portion is over-molded onto the compressionlimiter.
 4. The assembly component of claim 3, wherein the body includesradially inwardly extending anchor portions connected to a base portionof the body, wherein the free end is opposite a proximal end connectedto the base portion of the body, and wherein the compression limiter hasa channel in which a fixed portion of each radially inwardly extendinganchor portion is accommodated.
 5. The assembly component of claim 4,wherein each finger is unitary with the main body portion.
 6. Theassembly component of claim 4, wherein the base portion is unitary witheach finger.
 7. The assembly component of claim 1, wherein each fingerprojects radially and axially into the aperture in an unflexed state ofthe finger.
 8. The assembly component of claim 1, wherein the at leastone finger is a plurality of fingers that are circumferentially spacedabout the aperture.
 9. The assembly component of claim 1, wherein thethickness of each finger is less than a length of each finger,respectively.
 10. The assembly component of claim 1, wherein acircumferential length of each finger is greater than the thickness ofeach finger.
 11. The assembly component of claim 1, wherein thethickness of each finger is preferably 5%-25%, most preferably 10%-15%,the length of each finger, respectively.
 12. The assembly component ofclaim 1, further including a circumferential spacing between eachfinger.
 13. The assembly component of claim 12, wherein thecircumferential length of each finger is equal to or greater than acircumferential length of each circumferential spacing.
 14. A componentassembly including the assembly component of claim 1, further including:the shank of the fastener held within the aperture.
 15. A method ofsecuring a fastener to a body of an assembly component of claim 1,including: inserting a fastener into the aperture; and the free end ofeach finger being resiliently flexed radially and axially to apply agripping force to the shank of the fastener.
 16. The assembly componentof claim 1, wherein the compression limiter includes at least onechannel, and preferably a plurality of channels, for connecting to eachfinger of the body.
 17. The assembly component of claim 1, wherein theat least one resilient finger includes a radially inward extendingportion.
 18. The assembly component of claim 1, wherein the radiallyinward extending portion circumferentially spans the free end of thefinger.